noun an infectious dis-ease of children where the body is coveredwith a red rash She s in bed with measles. He s got measles.They caught measles from their friend at school.Have you had themeasles? Also called morbilli rubeola ( NOTE:Takes a singular or plural verb.)COMMENT: Measles can be a serious diseaseas it weakens the body s resistance to other diseases especially bronchitis and ear infec- tions. It can be prevented by immunisation. If caught by an adult it can be very serious.measure